Physical uplink shared channel power scaling to enhance power utilization at a user equipment

ABSTRACT

Certain aspects of the present disclosure provide techniques for scaling transmission power across transmit chains for physical uplink shared channel (PUSCH) transmissions. In some cases, a UE may determine a transmit power budget, receiving signaling indicating how to allocate the transmit power budget across transmit chains for a physical uplink shared channel (PUSCH) transmission, allocate the transmit power budget across transmit chains for a physical uplink shared channel (PUSCH) transmission, and transmitting the PUSCH using the transmit chains according to the determined transmit power allocation.

CLAIM OF PRIORITY UNDER 35 U.S.C. § 119

The present application for patent claims benefit of U.S. ProvisionalPatent Application Ser. Nos. 62/714,360, filed Aug. 3, 2018, 62/739,048,filed Sep. 28, 2018, and 62/832,789, filed Apr. 11, 2019, all of whichare assigned to the assignee hereof and hereby expressly incorporated byreference herein.

FIELD

Aspects of the present disclosure relate to wireless communications, andmore particularly, to techniques for scaling transmission power acrosstransmit chains for physical uplink shared channel (PUSCH)transmissions.

BACKGROUND

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,broadcasts, etc. These wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power, etc.). Examples of such multiple-access systems include3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)systems, LTE Advanced (LTE-A) systems, code division multiple access(CDMA) systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems, to name a few.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations (BSs), which are each capable ofsimultaneously supporting communication for multiple communicationdevices, otherwise known as user equipments (UEs). In an LTE or LTE-Anetwork, a set of one or more base stations may define an eNodeB (eNB).In other examples (e.g., in a next generation, a new radio (NR), or 5Gnetwork), a wireless multiple access communication system may include anumber of distributed units (DUs) (e.g., edge units (EUs), edge nodes(ENs), radio heads (RHs), smart radio heads (SRHs), transmissionreception points (TRPs), etc.) in communication with a number of centralunits (CUs) (e.g., central nodes (CNs), access node controllers (ANCs),etc.), where a set of one or more distributed units, in communicationwith a central unit, may define an access node (e.g., which may bereferred to as a base station, 5G NB, next generation NodeB (gNB orgNodeB), TRP, etc.). A base station or distributed unit may communicatewith a set of UEs on downlink channels (e.g., for transmissions from abase station or to a UE) and uplink channels (e.g., for transmissionsfrom a UE to a base station or distributed unit).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. New Radio (NR) (e.g., 5G) is an exampleof an emerging telecommunication standard. NR is a set of enhancementsto the LTE mobile standard promulgated by 3GPP. It is designed to bettersupport mobile broadband Internet access by improving spectralefficiency, lowering costs, improving services, making use of newspectrum, and better integrating with other open standards using OFDMAwith a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL).To these ends, NR supports beamforming, multiple-input multiple-output(MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in NR and LTEtechnology. Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communication by a userequipment (UE). The method generally includes determining a transmitpower budget, autonomously allocating the transmit power budget acrosstransmit chains for a physical uplink shared channel (PUSCH)transmission, and transmitting the PUSCH using the transmit chainsaccording to the determined transmit power allocation.

Certain aspects provide a method for wireless communication by a userequipment (UE). The method generally includes determining a transmitpower budget, receiving signaling indicating how to allocate thetransmit power budget across transmit chains for a physical uplinkshared channel (PUSCH) transmission, allocating the transmit powerbudget across transmit chains for a physical uplink shared channel(PUSCH) transmission, and transmitting the PUSCH using the transmitchains according to the determined transmit power allocation.

Certain aspects provide a method for wireless communication by a networkentity. The method generally includes transmitting, to a user equipment(UE), signaling indicating how to allocate a transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission and receiving the PUSCH transmitted from the UE withtransmit power allocated across transmit chains based on the signaling.

Certain aspects of the present disclosure also provide variousapparatus, means, and computer readable media capable of (or havinginstructions stored thereon for) performing the operations describedabove.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe appended drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the drawings. It is to be noted, however, thatthe appended drawings illustrate only certain typical aspects of thisdisclosure and are therefore not to be considered limiting of its scope,for the description may admit to other equally effective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed radio access network (RAN), in accordance with certainaspects of the present disclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample base station (BS) and user equipment (UE), in accordance withcertain aspects of the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a frame format for a new radio (NR)system, in accordance with certain aspects of the present disclosure.

FIG. 7 illustrates example operations that may be performed by a userequipment (UE), in accordance with aspects of the present disclosure.

FIG. 8 illustrates example operations that may be performed by a userequipment (UE), in accordance with aspects of the present disclosure.

FIG. 9 illustrates example operations that may be performed by a networkentity, in accordance with aspects of the present disclosure.

FIG. 10 illustrates example power boosting parameter values, inaccordance with aspects of the present disclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure present disclosure provide apparatus,methods, processing systems, and computer readable mediums for scalingtransmission power across transmit chains for physical uplink sharedchannel (PUSCH) transmissions.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition to,or other than, the various aspects of the disclosure set forth herein.It should be understood that any aspect of the disclosure disclosedherein may be embodied by one or more elements of a claim. The word“exemplary” is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication technologies, such as LTE, CDMA, TDMA, FDMA, OFDMA,SC-FDMA and other networks. The terms “network” and “system” are oftenused interchangeably. A CDMA network may implement a radio technologysuch as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRAincludes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implementa radio technology such as Global System for Mobile Communications(GSM). An OFDMA network may implement a radio technology such as NR(e.g. 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRAand E-UTRA are part of Universal Mobile Telecommunication System (UMTS).

New Radio (NR) is an emerging wireless communications technology underdevelopment in conjunction with the 5G Technology Forum (5GTF). 3GPPLong Term Evolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTSthat use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

New radio (NR) access (e.g., 5G technology) may support various wirelesscommunication services, such as enhanced mobile broadband (eMBB)targeting wide bandwidth (e.g., 80 MHz or beyond), millimeter wave (mmW)targeting high carrier frequency (e.g., 25 GHz or beyond), massivemachine type communications MTC (mMTC) targeting non-backward compatibleMTC techniques, and/or mission critical targeting ultra-reliablelow-latency communications (URLLC). These services may include latencyand reliability requirements. These services may also have differenttransmission time intervals (TTI) to meet respective quality of service(QoS) requirements. In addition, these services may co-exist in the samesubframe.

Example Wireless Communications System

FIG. 1 illustrates an example wireless communication network 100 inwhich aspects of the present disclosure may be performed. For example,UEs 120 may allocate transmit power according to operations describedbelow with reference to FIGS. 7 and 8. BSs 110 may perform operations ofFIG. 9 to configure a UE to perform operations shown in FIG. 8.

The wireless communication network 100 may be a New Radio (NR) or 5Gnetwork. As illustrated in FIG. 1, the wireless network 100 may includea number of base stations (BSs) 110 and other network entities. A BS maybe a station that communicates with user equipments (UEs). Each BS 110may provide communication coverage for a particular geographic area. In3GPP, the term “cell” can refer to a coverage area of a Node B (NB)and/or a Node B subsystem serving this coverage area, depending on thecontext in which the term is used. In NR systems, the term “cell” andnext generation NodeB (gNB), new radio base station (NR BS), 5G NB,access point (AP), or transmission reception point (TRP) may beinterchangeable. In some examples, a cell may not necessarily bestationary, and the geographic area of the cell may move according tothe location of a mobile BS. In some examples, the base stations may beinterconnected to one another and/or to one or more other base stationsor network nodes (not shown) in wireless communication network 100through various types of backhaul interfaces, such as a direct physicalconnection, a wireless connection, a virtual network, or the like usingany suitable transport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a subcarrier, afrequency channel, a tone, a subband, etc. Each frequency may support asingle RAT in a given geographic area in order to avoid interferencebetween wireless networks of different RATs. In some cases, NR or 5G RATnetworks may be deployed.

A base station (BS) may provide communication coverage for a macro cell,a pico cell, a femto cell, and/or other types of cells. A macro cell maycover a relatively large geographic area (e.g., several kilometers inradius) and may allow unrestricted access by UEs with servicesubscription. A pico cell may cover a relatively small geographic areaand may allow unrestricted access by UEs with service subscription. Afemto cell may cover a relatively small geographic area (e.g., a home)and may allow restricted access by UEs having an association with thefemto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for usersin the home, etc.). A BS for a macro cell may be referred to as a macroBS. A BS for a pico cell may be referred to as a pico BS. A BS for afemto cell may be referred to as a femto BS or a home BS. In the exampleshown in FIG. 1, the BSs 110 a, 110 b and 110 c may be macro BSs for themacro cells 102 a, 102 b and 102 c, respectively. The BS 110 x may be apico BS for a pico cell 102 x. The BSs 110 y and 110 z may be femto BSsfor the femto cells 102 y and 102 z, respectively. A BS may support oneor multiple (e.g., three) cells.

Wireless communication network 100 may also include relay stations. Arelay station is a station that receives a transmission of data and/orother information from an upstream station (e.g., a BS or a UE) andsends a transmission of the data and/or other information to adownstream station (e.g., a UE or a BS). A relay station may also be aUE that relays transmissions for other UEs. In the example shown in FIG.1, a relay station 110 r may communicate with the BS 110 a and a UE 120r in order to facilitate communication between the BS 110 a and the UE120 r. A relay station may also be referred to as a relay BS, a relay,etc.

Wireless network 100 may be a heterogeneous network that includes BSs ofdifferent types, e.g., macro BS, pico BS, femto BS, relays, etc. Thesedifferent types of BSs may have different transmit power levels,different coverage areas, and different impact on interference in thewireless network 100. For example, macro BS may have a high transmitpower level (e.g., 20 Watts) whereas pico BS, femto BS, and relays mayhave a lower transmit power level (e.g., 1 Watt).

Wireless communication network 100 may support synchronous orasynchronous operation. For synchronous operation, the BSs may havesimilar frame timing, and transmissions from different BSs may beapproximately aligned in time. For asynchronous operation, the BSs mayhave different frame timing, and transmissions from different BSs maynot be aligned in time. The techniques described herein may be used forboth synchronous and asynchronous operation.

A network controller 130 may couple to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another (e.g., directly or indirectly) via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a mobile station, a terminal, an access terminal,a subscriber unit, a station, a Customer Premises Equipment (CPE), acellular phone, a smart phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet computer, a camera, a gaming device, a netbook, a smartbook, anultrabook, an appliance, a medical device or medical equipment, abiometric sensor/device, a wearable device such as a smart watch, smartclothing, smart glasses, a smart wrist band, smart jewelry (e.g., asmart ring, a smart bracelet, etc.), an entertainment device (e.g., amusic device, a video device, a satellite radio, etc.), a vehicularcomponent or sensor, a smart meter/sensor, industrial manufacturingequipment, a global positioning system device, or any other suitabledevice that is configured to communicate via a wireless or wired medium.Some UEs may be considered machine-type communication (MTC) devices orevolved MTC (eMTC) devices. MTC and eMTC UEs include, for example,robots, drones, remote devices, sensors, meters, monitors, locationtags, etc., that may communicate with a BS, another device (e.g., remotedevice), or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things devices, which maybe narrowband Internet-of-Things devices.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kHz and the minimumresource allocation (called a “resource block” (RB)) may be 12subcarriers (or 180 kHz). Consequently, the nominal Fast FourierTransfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 forsystem bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz),respectively. The system bandwidth may also be partitioned intosubbands. For example, a subband may cover 1.08 MHz (i.e., 6 resourceblocks), and there may be 1, 2, 4, 8, or 16 subbands for systembandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR. NR may utilizeOFDM with a CP on the uplink and downlink and include support forhalf-duplex operation using TDD. Beamforming may be supported and beamdirection may be dynamically configured. MIMO transmissions withprecoding may also be supported. MIMO configurations in the DL maysupport up to 8 transmit antennas with multi-layer DL transmissions upto 8 streams and up to 2 streams per UE. Multi-layer transmissions withup to 2 streams per UE may be supported. Aggregation of multiple cellsmay be supported with up to 8 serving cells.

In some examples, access to the air interface may be scheduled, whereina. A scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. The scheduling entity may be responsible for scheduling,assigning, reconfiguring, and releasing resources for one or moresubordinate entities. That is, for scheduled communication, subordinateentities utilize resources allocated by the scheduling entity. Basestations are not the only entities that may function as a schedulingentity. In some examples, a UE may function as a scheduling entity andmay schedule resources for one or more subordinate entities (e.g., oneor more other UEs), and the other UEs may utilize the resourcesscheduled by the UE for wireless communication. In some examples, a UEmay function as a scheduling entity in a peer-to-peer (P2P) network,and/or in a mesh network. In a mesh network example, UEs may communicatedirectly with one another in addition to communicating with a schedulingentity.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A finely dashed line withdouble arrows indicates interfering transmissions between a UE and a BS.

FIG. 2 illustrates an example logical architecture of a distributedRadio Access Network (RAN) 200, which may be implemented in the wirelesscommunication network 100 illustrated in FIG. 1. A 5G access node 206may include an access node controller (ANC) 202. ANC 202 may be acentral unit (CU) of the distributed RAN 200. The backhaul interface tothe Next Generation Core Network (NG-CN) 204 may terminate at ANC 202.The backhaul interface to neighboring next generation access Nodes(NG-ANs) 210 may terminate at ANC 202. ANC 202 may include one or moretransmission reception points (TRPs) 208 (e.g., cells, BSs, gNBs, etc.).

The TRPs 208 may be a distributed unit (DU). TRPs 208 may be connectedto a single ANC (e.g., ANC 202) or more than one ANC (not illustrated).For example, for RAN sharing, radio as a service (RaaS), and servicespecific AND deployments, TRPs 208 may be connected to more than oneANC. TRPs 208 may each include one or more antenna ports. TRPs 208 maybe configured to individually (e.g., dynamic selection) or jointly(e.g., joint transmission) serve traffic to a UE.

The logical architecture of distributed RAN 200 may support fronthaulingsolutions across different deployment types. For example, the logicalarchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The logical architecture of distributed RAN 200 may share featuresand/or components with LTE. For example, next generation access node(NG-AN) 210 may support dual connectivity with NR and may share a commonfronthaul for LTE and NR.

The logical architecture of distributed RAN 200 may enable cooperationbetween and among TRPs 208, for example, within a TRP and/or across TRPsvia ANC 202. An inter-TRP interface may not be used.

Logical functions may be dynamically distributed in the logicalarchitecture of distributed RAN 200. As will be described in more detailwith reference to FIG. 5, the Radio Resource Control (RRC) layer, PacketData Convergence Protocol (PDCP) layer, Radio Link Control (RLC) layer,Medium Access Control (MAC) layer, and a Physical (PHY) layers may beadaptably placed at the DU (e.g., TRP 208) or CU (e.g., ANC 202).

FIG. 3 illustrates an example physical architecture of a distributedRadio Access Network (RAN) 300, according to aspects of the presentdisclosure. A centralized core network unit (C-CU) 302 may host corenetwork functions. C-CU 302 may be centrally deployed. C-CU 302functionality may be offloaded (e.g., to advanced wireless services(AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU 304 may host core network functions locally. TheC-RU 304 may have distributed deployment. The C-RU 304 may be close tothe network edge.

A DU 306 may host one or more TRPs (Edge Node (EN), an Edge Unit (EU), aRadio Head (RH), a Smart Radio Head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of BS 110 and UE 120 (as depictedin FIG. 1), which may be used to implement aspects of the presentdisclosure. For example, antennas 452, processors 466, 458, 464, and/orcontroller/processor 480 of the UE 120 and/or antennas 434, processors420, 460, 438, and/or controller/processor 440 of the BS 110 may be usedto perform the various techniques and methods described herein.

At the BS 110, a transmit processor 420 may receive data from a datasource 412 and control information from a controller/processor 440. Thecontrol information may be for the physical broadcast channel (PBCH),physical control format indicator channel (PCFICH), physical hybrid ARQindicator channel (PHICH), physical downlink control channel (PDCCH),group common PDCCH (GC PDCCH), etc. The data may be for the physicaldownlink shared channel (PDSCH), etc. The processor 420 may process(e.g., encode and symbol map) the data and control information to obtaindata symbols and control symbols, respectively. The processor 420 mayalso generate reference symbols, e.g., for the primary synchronizationsignal (PSS), secondary synchronization signal (SSS), and cell-specificreference signal (CRS). A transmit (TX) multiple-input multiple-output(MIMO) processor 430 may perform spatial processing (e.g., precoding) onthe data symbols, the control symbols, and/or the reference symbols, ifapplicable, and may provide output symbol streams to the modulators(MODs) 432 a through 432 t. Each modulator 432 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. Downlink signals from modulators 432 a through 432 tmay be transmitted via the antennas 434 a through 434 t, respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) in transceivers 454 a through 454 r,respectively. Each demodulator 454 may condition (e.g., filter, amplify,downconvert, and digitize) a respective received signal to obtain inputsamples. Each demodulator may further process the input samples (e.g.,for OFDM, etc.) to obtain received symbols. A MIMO detector 456 mayobtain received symbols from all the demodulators 454 a through 454 r,perform MIMO detection on the received symbols if applicable, andprovide detected symbols. A receive processor 458 may process (e.g.,demodulate, deinterleave, and decode) the detected symbols, providedecoded data for the UE 120 to a data sink 460, and provide decodedcontrol information to a controller/processor 480.

On the uplink, at UE 120, a transmit processor 464 may receive andprocess data (e.g., for the physical uplink shared channel (PUSCH)) froma data source 462 and control information (e.g., for the physical uplinkcontrol channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a reference signal(e.g., for the sounding reference signal (SRS)). The symbols from thetransmit processor 464 may be precoded by a TX MIMO processor 466 ifapplicable, further processed by the demodulators in transceivers 454 athrough 454 r (e.g., for SC-FDM, etc.), and transmitted to the basestation 110. At the BS 110, the uplink signals from the UE 120 may bereceived by the antennas 434, processed by the modulators 432, detectedby a MIMO detector 436 if applicable, and further processed by a receiveprocessor 438 to obtain decoded data and control information sent by theUE 120. The receive processor 438 may provide the decoded data to a datasink 439 and the decoded control information to the controller/processor440.

The controllers/processors 440 and 480 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 440 and/orother processors and modules at the B S 110 may perform or direct theexecution of processes for the techniques described herein. The memories442 and 482 may store data and program codes for BS 110 and UE 120,respectively. A scheduler 444 may schedule UEs for data transmission onthe downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a wireless communication system,such as a 5G system (e.g., a system that supports uplink-basedmobility). Diagram 500 illustrates a communications protocol stackincluding a Radio Resource Control (RRC) layer 510, a Packet DataConvergence Protocol (PDCP) layer 515, a Radio Link Control (RLC) layer520, a Medium Access Control (MAC) layer 525, and a Physical (PHY) layer530. In various examples, the layers of a protocol stack may beimplemented as separate modules of software, portions of a processor orASIC, portions of non-collocated devices connected by a communicationslink, or various combinations thereof. Collocated and non-collocatedimplementations may be used, for example, in a protocol stack for anetwork access device (e.g., ANs, CUs, and/or DUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device. In the second option, RRC layer 510, PDCP layer 515, RLClayer 520, MAC layer 525, and PHY layer 530 may each be implemented bythe AN. The second option 505-b may be useful in, for example, a femtocell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack as shownin 505-c (e.g., the RRC layer 510, the PDCP layer 515, the RLC layer520, the MAC layer 525, and the PHY layer 530).

In LTE, the basic transmission time interval (TTI) or packet duration isthe 1 ms subframe. In NR, a subframe is still 1 ms, but the basic TTI isreferred to as a slot. A subframe contains a variable number of slots(e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing.The NR RB is 12 consecutive frequency subcarriers. NR may support a basesubcarrier spacing of 15 KHz and other subcarrier spacing may be definedwith respect to the base subcarrier spacing, for example, 30 kHz, 60kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with thesubcarrier spacing. The CP length also depends on the subcarrierspacing.

FIG. 6 is a diagram showing an example of a frame format 600 for NR. Thetransmission timeline for each of the downlink and uplink may bepartitioned into units of radio frames. Each radio frame may have apredetermined duration (e.g., 10 ms) and may be partitioned into 10subframes, each of 1 ms, with indices of 0 through 9. Each subframe mayinclude a variable number of slots depending on the subcarrier spacing.Each slot may include a variable number of symbol periods (e.g., 7 or 14symbols) depending on the subcarrier spacing. The symbol periods in eachslot may be assigned indices. A mini-slot, which may be referred to as asub-slot structure, refers to a transmit time interval having a durationless than a slot (e.g., 2, 3, or 4 symbols).

Each symbol in a slot may indicate a link direction (e.g., DL, UL, orflexible) for data transmission and the link direction for each subframemay be dynamically switched. The link directions may be based on theslot format. Each slot may include DL/UL data as well as DL/UL controlinformation.

In NR, a synchronization signal/physical broadcast channel (SS/PBCH)block is transmitted (also referred to as a synchronization signal block(SSB)). The SS/PBCH block includes a PSS, a SSS, and a two symbol PBCH.The SS/PBCH block can be transmitted in a fixed slot location, such asthe symbols 2-5 as shown in FIG. 6. The PSS and SSS may be used by UEsfor cell search and acquisition. The PSS may provide half-frame timing,the SS may provide the CP length and frame timing. The PSS and SSS mayprovide the cell identity. The PBCH carries some basic systeminformation, such as downlink system bandwidth, timing informationwithin radio frame, SS burst set periodicity, system frame number, etc.The SS/PBCH blocks may be organized into SS bursts to support beamsweeping. Further system information such as, remaining minimum systeminformation (RMSI), system information blocks (SIBs), other systeminformation (OSI) can be transmitted on a physical downlink sharedchannel (PDSCH) in certain subframes.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications,Internet-of-Things communications, mission-critical mesh, and/or variousother suitable applications. Generally, a sidelink signal may refer to asignal communicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

Example PUSCH Power Scaling to Enable Full Power Utilization at the UE

Aspects of the present disclosure provide techniques for scalingtransmission power across transmit chains for physical uplink sharedchannel (PUSCH) transmissions.

As used herein, a transmit chain generally refers to a set of componentsin a signal path to take a baseband signal and generate an RF signal.Example transmit chain components include digital to analog converters(DACs), modulators, power amplifiers (PAs), as well as various filtersand switches. Conversely, a receive chain generally refers to a set ofcomponents in a signal path to take an RF signal and generate a basebandsignal. Example receive chain components include downconverts,demodulators, and analog to digital converters (ADCs), as well asvarious filters and switches.

For uplink data transmissions, according to a conventional PUSCH powerscaling approach, a UE is assigned a single transmission (Tx) powerbudget that is to be split uniformly across all available transmitchains and the assigned RBs.

Unfortunately, there can be scenarios where the UE is unable to transmitat the full power when splitting the Tx power budget uniformly accordingto the conventional approach. For example, one such scenario is the casewhere a UE has four Tx chains, and is assigned the precoder [1 1 0 0].If the UE is assigned a transmit power budget of P__(PUSCH), then the UEis expected to scale transmission power according to a multi-stepprocedure such as the following 2-step algorithm:

-   -   (a) scale this power by the ratio of a number of antenna ports        with a non-zero PUSCH transmission to a number of configured        antenna ports, the    -   (b) split the resulting scaled power equally across the antenna        ports on which non-zero PUSCH is to be transmitted.

When the 2-step algorithm is followed as is, for the above example offour TX chains and a precoder [1 1 0 0], step (a) results in a scaledpower of P__(PUSCH)/2 which, in step (b), is split equally among the twoports that carry non-zero PUSCH. Thus, two ports are assignedP__(PUSCH)/4 each, resulting is only half the Tx power budget beingutilized.

Aspects of the present disclosure provide techniques that may helpaddress this issue by providing new power allocation methods andsignaling mechanisms. The techniques may help more efficiently utilizeTx power budget, particularly in UEs with transmit chains that haveheterogeneous power amplifiers (PAs) and coherent/noncoherent antennas.As used herein, heterogeneous generally refers to PAs that havedifferent output power ratings.

The following description assumes the following notation:

-   -   N refers to the number of configured antenna ports;    -   K refers to the number of antenna ports with non-zero PUSCH;    -   P__(PUSCH) refers to the PUSCH transmission power budget;    -   P_a refers to the scaled transmission power obtained after Step        (a); and    -   P_b refers to the power allocated to each port transmitting        non-zero PUSCH after Step (b).

According to one proposed solution, a UE may be allowed to autonomouslydetermine its own transmit power allocation. In this context, autonomousmeans the UE may allocate its Tx power budget as it sees fit, forexample, without additional signaling from a base station.

FIG. 7 illustrates example operations 700 for autonomous scalingtransmission power of PUSCH transmissions by a user equipment (UE), inaccordance with aspects of the present disclosure. For example,operations 700 may be performed by a UE 120 shown in FIGS. 1 and 4.

Operations 700 begin, at 702, by determining a transmit power budget. At704, the UE autonomously allocates the transmit power budget acrosstransmit chains for a physical uplink shared channel (PUSCH)transmission. At 706, the UE transmits the PUSCH using the transmitchains according to the determined transmit power allocation.

In this case, a UE assigned a target P__(PUSCH) may be allowed to splitthis power across multiple Tx chains as it decides, provided itpreserves the integrity of any precoder assigned for PUSCH transmission.As used herein, integrity generally refers to the impact of powerallocation being equivalent to scaling the precoders by a scalar value.In this case, with a UE allowed to autonomously determine powerallocation, steps (a) and (b) of the 2-step algorithm described abovemay be ignored.

This autonomous approach may provide the UE with maximum flexibility inallocating the transmit power. This approach may be particularlybeneficial to UEs with heterogeneous PAs in their transmit chains. Asthe base station is not likely to know output power ratings of theheterogeneous PAs, the UE is best positioned to determine the rightallocation of power among the transmit chains, for example, by factoringin the individual output power rating of the PAs powering each transmitchain.

This autonomous approach may be considered an open loop scheme as itdoes not require additional signaling from the gNB (e.g., beyond theinitial signaling of target P__(PUSCH)), which is in contrast to othertechniques described below.

In other words, in these other techniques, a network entity (e.g., agNB) may provide signaling to a UE that determines how the UE performsTx power scaling.

FIG. 8 illustrates example operations 800 that may be performed by a UEfor scaling transmission power of PUSCH transmissions based on networksignaling, in accordance with aspects of the present disclosure. Forexample, operations 800 may be performed by a UE 120 shown in FIGS. 1and 4.

Operations 800 begin, at 802, by determining a transmit power budget. At804, the UE receives signaling indicating how to allocate the transmitpower budget across transmit chains for a physical uplink shared channel(PUSCH) transmission. At 806, the UE allocates the transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission. At 808, the UE transmits the PUSCH using the transmitchains according to the determined transmit power allocation.

FIG. 9 illustrates example operations 900 for wireless communications bya network entity, such as an eNB, in accordance with aspects of thepresent disclosure. For example, operations 900 may be performed by aBS/gNB 110 shown in FIGS. 1 and 4 to signal a UE to perform transmissionpower scaling according the operations of FIG. 8 described above.

Operations 900 begin, at 902, by transmitting, to a user equipment (UE),signaling indicating how to allocate a transmit power budget acrosstransmit chains for a physical uplink shared channel (PUSCH)transmission. At 904, the network entity receives the PUSCH transmittedfrom the UE with transmit power allocated across transmit chains basedon the signaling.

In some cases, the Tx power scaling may be provided via a single bit(1-bit) signaling. For example, a gNB may provide a single bit thatindicates whether the UE can skip part of the two-step algorithmdescribed above. For example, the single bit may selectively turn on/offperforming step (a) described above, while step (b) may always performed(regardless of the signaled bit value). The single bit may be provided,for example, via a grant that schedules a PUSCH or via some other typeof signaling.

By skipping the initial scaling step (a), the entire Tx power budget maybe assigned among the ports that transmit non-zero PUSCH.

The effect of this change may be demonstrated by considering the sameexample presented above, where a UE has four Tx chains, and is assignedthe precoder [1 1 0 0]. In this example, if step (a) is disabled (the UEis allowed to skip this step), then each of two ports that transmitnon-zero PUSCH are assigned P__(PUSCH)/2 power (rather than P__(PUSCH)/4as per the conventional algorithm where the initial scaling isperformed). Thus, in this example, the entire allocated Tx power budgetis used.

Certain UEs may not be able to skip the scaling step even if allowed to,for example, depending on the output power rating of their poweramplifiers. To address this case, some UEs may be configured to signal(e.g., an explicitly indication) of whether they can support this 1-bitsignaling or not. This indication may be provided, for example, as UEcapability information. As an alternative, UEs may be allowed toimplicitly ignore this signaling and continue to perform both Step (a)and Step (b).

In some cases, the gNB may provide multi-bit signaling indicating how aUE is to perform transmit power scaling. For example, the gNB mayprovide multi-bit signaling for the UE to perform transmit power scalingaccording to a common power boosting. This alternative to the single-bitapproach may provide a more fine grained approach to power allocationthat can be enabled by adding a third step, a “Step (c)” to the firsttwo steps already described above.

In this Step (c), the UE may be allowed to further alter the power asobtained from steps (a) and (b) via a common power boosting factor α.For example, assuming α is a 2-bit signaling parameter, α may indicatethe values shown in FIG. 10. Thus, using 2-bits in this example, a gNBcan enable boosting the power obtained after step (b) by one of fourvalues (e.g., an additional 0, 1, 2, or 3 dB).

Power boosting in this manner may be described, assuming the sameexample as above, where a UE has 4 Tx chains, and is assigned theprecoder [1 1 0 0]. In this example, steps (a) and (b) are followed bystep (c) where a is indicated as ‘11.’ In this case, using thealpha-power boost table as shown in FIG. 10, each port is allowed toboost its power by an additional 3 dB, such that the effective power perport is P__(PUSCH)/2. Thus, it is easy to see that once again the UE isable to use all available power using this method.

This result may be understood more easily by considering that thesignaled α for Step (c) corresponds to a boost of β__(dB) in dB scale orequivalently β__(linear) in the linear scale. Thus, the new powerassigned to each port is P_c=P_b×β__(linear). In the example above, a 3dB corresponds to a 2× gain in the linear scale and, hence, a gain fromP__(PUSCH)/4 to P__(PUSCH)/2.

Of course, the signaling of parameter α using 2-bits is an example only.In some cases, more than 2-bits may be used to achieve finergranularity.

In some cases, one or more actions may be taken (at the gNB and/or UE)to ensure that the power boosting in Step (c) does not end up exceedingan originally assigned power of P__(PUSCH). For example, such actionsmay include:

-   -   (1) Preventing such cases altogether. For example, only those        values of a that ensure the total assigned power across the        ports does not exceed P__(PUSCH) may be considered valid or        permitted. Signaling by the gNB may ensure the power allocation        is valid, so that such cases do not arise (e.g., a gNB may        consider the impact of the signaled boost and only signal valid        values);    -   (2) Step (c) may be ignored for cases where the power boosting        would result in P__(PUSCH) being exceeded. In this case,        β__(line) may effectively default to 1;    -   (3) As an alternative to the above, if the total power        constraint is violated (P__(b)×β__(linear)×K≥P__(PUSCH)), then        P_c can be set as:        P_c=min(P_ _(b)×/β__(linear) ,P_ _(PUSCH) /K)

These fallback mechanisms allow decoupling of the signaling of theprecoder and the common power boosting factor. This may help simplifysignaling, as a common power boosting factor can be indicated once, andused across several precoders, with K reflecting the number of portswith non-zero PUSCH for each signaled precoder.

In the preceding discussion, it may be important that the power P_cassigned to a port with non-zero PUSCH transmission does not exceed themaximum output power rating of the power amplifier on that antenna port.To avoid such a scenario, the UE may signal/report its (RF) capabilityto the eNB. This signaling may indicate, for example, a maximum commonpower boost supported by the UE.

In some cases, as an extension to signaling a multi-bit power boostparameter as described above, the power boosting factor can be specifiedon a per-port basis (i.e., α₁, α₂, . . . , α_(N) assuming N ports). Thisapproach may allow even greater flexibility in how each port is assigneda transmit power.

This per-port method may be described by assuming an example whereP__(b) is the power assigned per port after steps (a) and (b) and thesignaled α_(i) for Step (c) corresponds to a boost of β__((i,dB)) in dBscale or equivalently β__((i,linear)). In the linear scale, then, thenew power assigned to the i^(th) port according to this approach is:P_ _((c,i)) =P_ _(b)×β__((i,linear)).In some cases, the bit-width of each α_(i) may be different.

If the ports with non-zero PUSCH are known apriori, then it suffices toonly signal values of α_(i) for the ports with non-zero PUSCH (althoughadditional signaling may be required if/when the precoder changes).Alternatively, the per-port power boosting values (corresponding todifferent precoding) can be signaled once for all the antenna ports andused across several transmission even when precoding changes.

Similar to the single value case above, steps may be taken in the“per-port” case to ensure that the power boosting in Step (c) does notexceed the original assigned power of P__(PUSCH). In other words, thesesteps may be taken to ensure that:Σ_(n=1) ^(N) P _(b)β_(n,linear) ≤P _(PUSCH),For example, such actions may include:

-   -   (1) Preventing such cases altogether. For example, only those        values of α is that ensure the total assigned power across the        ports does not exceed P_PUSCH may be considered valid or        permitted. Signaling by the gNB may ensure the power allocation        is valid, so that such cases do not arise;    -   (2) Step (c) may be ignored for such cases, effectively meaning        β_n, linear defaults to 1 for all ports;    -   (3) Alternately, if the total power constraint is violated,        meaning:        Σ_(n=1) ^(N) P _(b)β_(n,linear) ≥P _(PUSCH),    -   then P_c,i can be set as P_PUSCH/K for all ports that transmit        non-zero PUSCH.

These fallback mechanisms effectively allow decoupling the signaling ofthe precoder and the per-port power boosting factors. Per-port powerboosting factors can be indicated once, and used across severalprecoders, with K reflecting the number of ports with non-zero PUSCH foreach signaled precoder. In the preceding discussion, it may be importantthat the power P_c,i assigned to a port with non-zero PUSCH transmissiondoes not exceed the maximum output power rating of the power amplifieron that antenna port. To avoid such a scenario, the UE may signal/reportRF capability to eNB on the maximum per-port power boost supported bythe UE.

Aspects of the present disclosure also provide various additionalfeatures that may be considered enhancements for cases where a UE isallowed to determine power allocation for a PUSCH transmission. Theenhancements may be applicable, for example, to any power allocationscheme where a UE is provided with some level of autonomy or when the UEimplementation is not known to gNB.

In some such cases, a value indicated (by a UE) in a power headroomreport (PHR) accompanying the PUSCH transmission may be dependent on atransmit precoding matrix indicator (TPMI) used for the PUSCHtransmission. In general, each TPMI may have a different PHR value, forexample, due to different characteristics in the power amplifiers usedin the different transmit chains associated with the different TPMIs.

Because of this, when a UE is allowed to determine power allocationautonomously, the actual transmit power used by the UE can beTPMI-dependent. In other words, a PHR based on a slot with a PUSCHtransmission may also be dependent on the exact TPMI used in that slot.This may be illustrated by considering an example of a UE with 2 antennaports:

-   -   (1) a first port having a 20 dBm PA; and    -   (2) a second port having a 23 dBm PA.        Assuming the UE is asked to a transmit at 17 dBm power then, for        a TPMI corresponding to the precoder [1, 0], which selects the        first port, the PHR should indicate a headroom of 3 dB (20        dBm-17 dBm). On the other hand, if the TPMI corresponds to the        precoder [0 1], selecting the second port, the PHR should        indicate a headroom of 6 dB (20 dBm-14 dBm).

For this reason, the PHR that accompanies the PUSCH transmission shouldindicate the appropriate value for the TPMI used in that slot. In somecases, it may not be necessary to explicitly tag (or signal) the exactTPMI, as the gNB may already know the TPMI used, so it can track this onits end.

Given the PHR signaled in this example is for a particular TPMI, it maybe important that the UE keep its implementation/configurationconsistent over a certain period of time. For example, it may bedesirable that the UE avoid dynamically switching the port to Tx-chainmapping too frequently (every slot).

As noted above, in some cases, a gNB may provide one or more bits ofsignaling to indicate whether a UE is to allocate power in a mannerdifferent from a conventional approach (e.g., what is currentlyspecified in a standard). In some cases, however, a UE may not beallowed to deviate from what is specified (e.g., a UE may not be able toskip a power scaling step). Therefore, it may be desirable for a UE toindicate support for this feature (e.g., during call setup) as notedabove.

Further, in some cases, whether a UE supports this particular feature(or similar features) may depend on one or more band combinationssupported by the UE for carrier aggregation (CA).

For example, if there are three component carriers (cc1, cc2 and cc3),the UE may support combinations cc1+cc3 and cc2+cc3. Thus, in additionto indicating support for these band combinations in general, the UE mayalso indicate, for each supported band combination, whether a change tothe power allocation rule is supported or not.

In some cases, the UE may provide a pair of bits the values of whichindicate whether or not the UE supports a new power allocation rule foreach of the band combinations supported. For example, assuming the bitcombinations from the example above, if the UE supports a new rule forthe cc1+cc3 combination, but not for the cc2+cc3 combination, then theUE may signal the following pairs: [Cc1+cc3, b=1] and [cc2+cc3, b=0],where bit b is used to indicate support for the new power allocationrule.

As discussed above, antennas may have different antenna coherence. Incertain systems, antennas may be classified as coherent, non-coherent,or partially-coherent. Two antenna ports are said to be coherent, forexample, if their relative phase remains constant between the time ofsounding reference signal (SRS) transmission and a subsequent physicaluplink shared channel (PUSCH) transmission using the same ports. PUSCHprecoding may be impacted by the antenna coherence. Coherent antennascan act in unison (e.g., their relative phases stay constant) andprecoding can span across all antennas. Non-coherent antennas actindependently of each other and precoding across antennas is notmaintained. Partially-coherent antennas may include a subset of antennasthat are coherent, but might not be coherent across these subsets, andprecoding spans only across the coherent sets of antennas.

In certain systems with different antenna coherence, PUSCH transmissionsmay be limited to (e.g., restricted to) coherent sets of antennas. Inthis case, the precoder codebook may be limited to the coherentantennas. Thus, some antennas (e.g., the antennas that are not coherent)are not used for transmitting PUSCH. Without use of these antennas,PUSCH transmission may not be at full power.

As discussed above, in some examples, transmission at full power may bepossible if a power allocation rule, e.g., following the conventional2-step algorithm for the UE to scale transmission power, is modified.

In some cases, a UE may support full uplink transmission power with fullrates on each transmit (TX) chain. For example, such a UE may have apower class (e.g., referred to as PC3) having 23 dBm and 23 dBm PAs(e.g., for a UE with two TX chains). This may be referred to as a UEcapability 1 or a “cap1” UE.

In some cases, a UE may support full uplink transmission power with noTX chains assumed to deliver full rate power (e.g., none having a fullPA). For example, the UE can have a power class (e.g., PC3) having 20dBm and 20 dBm PAs (e.g., for a UE with two TX chains). This may bereferred to as a UE capability 2 or a “cap2” UE.

In some cases, a UE may support full uplink transmission power with asubset of TX chains with full rated PAs. For example, the UE can have apower class (e.g., PC3) having 23 dBm and 20 dBm PAs (e.g., for a UEwith two TX chains). This may be referred to as a UE capability 3 or a“cap3” UE.

In some cases, a single bit (b) may be used to indicate whether the UEsupports full power. For example, the UE can indicate a power scalingfactor (e.g., set a bit equal to 1) to indicate that the step (a) of the2-step scaling algorithm can be skipped, or the UE can set a powerscaling factor (e.g., to zero), or select a number of non-zero powerand/or number of total ports in a SRS resource, to indicate that thestep (a) of the 2-step scaling algorithm is not skipped (e.g., aconventional power scaling algorithm is followed/adhered to).

In some cases, a cap1 UE may be configured to always skip the step (a)(e.g., set the bit to 1) and a cap2 UE may be configured to alwaysadhere to the step (a) (e.g., set the bit to 0). In an illustrativeexample, b=1 may indicate that the UE supports full power with powerscaling factor equal to 1 (always); b=0 may indicate that the UEsupports full power with power scaling factor equals to #nonzeroports/#total ports in a SRS resource. In some examples (e.g., for cap3UEs), the UE may signal a single bit (b) per transmit precoding matrixindicator (TPMI), or per TPMI group, to indicate whether the UE supportsfull power for that TPMI/TPMI group.

In some examples, certain TPMIs may categorized based on their use forcertain TPMIs. For example, certain TPMIs may be categorized as TPMIsthat can only be used by coherent UEs, TPMIs that can only be used bycoherent and partially-coherent UEs, or TPMIs that may only be used bycoherent, partially-coherent, and non-coherent UEs. Thus, a broadcodebook may be configured for coherent UEs, and subsets of thiscoherent codebook may be used for non-coherent and partially coherentUEs.

In some examples, a UE may indicate a list of up to K TPMIs for whichstep (a) of the 2-step scaling algorithm is skipped. For these TPMIs,the UE skips the first step of the power scaling rule and only followsthe second step. The list of TPMIs, for which step (a) can be skipped,may be selected from the coherent codebook set (e.g., may not be limitedto codebook subsets that are allowed for non-coherent orpartially-coherent UEs).

In an illustrative example, a cap2 non-coherent PC3 UE with four 17 dBmPAs can list a single TPMI [1 1 1 1] (from the coherent codebook set).While the TPMI [1 1 1 1] may not normally be allowed for thenon-coherent UE, this indication can implicitly indicate to the gNB thatUE can support full power on the TPMI. For example, the UE may supportfull power on the TPMI via a cyclic diversity delay (CDD)implementation. The CCD may add an additional (cyclic) delay to oneprecoded port, and not to another port. The different delays fordifferent ports may add further incoherency. In this example, the powerscaling rule steps may not actually be skipped (e.g., because allantenna ports are used, it is not impacted by the step (a) rule), butthe availability of a CDD solution may be indicated to the gNB. Inanother illustrative example, a cap3 non-coherent PC3 UE with two 17 dBmPAs and two 20 dBm PAs can list TPMIs [1 1 1 1] and [0 0 1 1] to thegNB.

The methods disclosed herein comprise one or more steps or actions forachieving the methods. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language of the claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112(f) unless the element is expressly recited using the phrase“means for” or, in the case of a method claim, the element is recitedusing the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components. Forexample, various operations shown in FIGS. 7, 8 and 9 may be performedby various processors shown in FIG. 4. More particularly, operations 700and 800 of FIGS. 7 and 8 may be performed by one or more of processors466, 458, 464, and/or controller/processor 480 of the UE 120, whileoperations 900 of FIG. 9 may be performed by processors 420, 460, 438,and/or controller/processor 440 of the BS 110 shown in FIG. 4.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For example, instructions for performing the operationsdescribed herein and illustrated in FIGS. 7, 8, and/or 9.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method of wireless communications by a userequipment (UE), comprising: determining a transmit power budget;receiving signaling indicating how to allocate the transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission, wherein the signaling indicates whether or not the UE canskip scaling the transmit power budget by a ratio of a number of antennaports with a non-zero PUSCH transmission to a total number of configuredantenna ports; allocating the transmit power budget across the transmitchains for the PUSCH transmission when the scaling is skipped orallocating the scaled transmit power budget across the transmit chainswhen the scaling is not skipped; and sending the PUSCH transmissionusing the transmit chains according to the allocated transmit powerbudget.
 2. The method of claim 1, further comprising providing signalingindicating whether the UE supports skipping the scaling.
 3. The methodof claim 2, wherein the allocating comprises allocating the transmitpower budget across transmit chains for one or more band combinationssupported by the UE for carrier aggregation.
 4. The method of claim 3,wherein the signaling provided by the UE indicates at least one of theone or more band combinations for which the UE supports skipping theallocating the transmit power budget across transmit chains.
 5. Themethod of claim 1, wherein the UE is configured to perform the scaling,regardless of the signaling, depending on a rating of power amplifiersin the transmit chains.
 6. A method of wireless communications by a userequipment (UE), comprising: determining a transmit power budget;receiving signaling indicating how to allocate the transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission, wherein the signaling comprises multiple bits thatindicate at least one power boosting parameter for the UE to apply afterallocating the transmit power budget across the transmit chains;allocating the transmit power budget across the transmit chains for thePUSCH transmission; and sending the PUSCH transmission using thetransmit chains according to the allocated transmit power budget and theat least one power boosting parameter.
 7. The method of claim 6, furthercomprising providing signaling indicating a level of power boostingsupported by the UE.
 8. The method of claim 7, further comprisingcomputing the level of power boosting supported by the UE based on areference power level and a power rating of one or more power amplifiersin the transmit chains.
 9. The method of claim 6, further comprisingtaking one or more actions to ensure applying the power boostingparameter does not result in exceeding the transmit power budget. 10.The method of claim 6, wherein: the multiple bits indicate the at leastone power boosting parameter for the UE to apply on a per-port basis.11. The method of claim 10, wherein the signaling provided by the UEcomprises at least one of: power boosting parameters for different portswith different bit-widths; an indication of power boosting parametersfor only ports with non-zero PUSCH as indicated by a precoder;additional signaling of power boosting parameters if the precoderchanges; or an indication of power boosting parameters for all antennaports regardless of a precoder, wherein the power boosting parametersare applied, on a per-port basis, across multiple transmissions evenwhen the precoder changes.
 12. The method of claim 1, further comprisingproviding signaling indicating whether the UE supports skipping at leastone step of a multi-step procedure for allocating the transmit powerbudget across transmit chains.
 13. The method of claim 12, wherein thesignaling provided by the UE comprises at least one of: a single bitindicating whether the UE supports the skipping; a single bit pertransmit precoding matrix indicator (TPMI) or TPMI group indicatingwhether the UE supports the skipping for the TPMI or TPMI group; or alist of transmit precoding matrix indicators (TPMIs) for which the UEsupports skipping at least one step of a multi-step procedure forallocating the transmit power budget across transmit chains.
 14. Amethod of wireless communications by a network entity, comprising:transmitting, to a user equipment (UE), signaling indicating how toallocate a transmit power budget across transmit chains for a physicaluplink shared channel (PUSCH) transmission, wherein the signalingindicates whether or not the UE can skip scaling the transmit powerbudget by a ratio of a number of antenna ports with a non-zero PUSCHtransmission to a total number of configured antenna ports; andreceiving the PUSCH transmitted from the UE with transmit powerallocated across the transmit chains when the signaling indicates the UEcan skip scaling or with a scaled transmit power allocated across thetransmit chains when the signaling indicates the UE cannot skip scaling.15. The method of claim 14, further comprising receiving signalingindicating whether the UE supports skipping the scaling.
 16. A method ofwireless communications by a network entity, comprising: transmitting,to a user equipment (UE), signaling indicating how to allocate atransmit power budget across transmit chains for a physical uplinkshared channel (PUSCH) transmission, wherein the signaling transmittedto the UE comprises multiple bits that indicate at least one powerboosting parameter for the UE to apply after performing a multi-stepprocedure for allocating the transmit power budget across the transmitchains; and receiving the PUSCH transmitted from the UE with transmitpower allocated across the transmit chains based on the signaling. 17.The method of claim 16, further comprising: receiving signaling from theUE indicating a level of power boosting supported by the UE; anddetermining the at least one power boosting parameter based on theindicated level of power boosting supported by the UE.
 18. The method ofclaim 16, wherein: the multiple bits indicate the at least one powerboosting parameter for the UE to apply on a per-port basis.
 19. Themethod of claim 18, wherein the signaling indicating how to allocate thetransmit power budget across the transmit chains for the PUSCHtransmission comprises at least one of: power boosting parameters fordifferent ports with different bit-widths; an indication of powerboosting parameters for only ports with non-zero PUSCH as indicated by aprecoder; additional signaling of power boosting parameters if theprecoder changes; or an indication of power boosting parameters for allantenna ports regardless of a precoder, wherein the power boostingparameters are applied, on a per-port basis, across multipletransmissions even when the precoder changes.
 20. The method of claim14, further comprising receiving signaling from the UE that indicatesone or more band combinations for which the UE supports a procedure toallocate power across transmit chains.
 21. The method of claim 20,wherein the signaling indicating how to allocate the transmit powerbudget across the transmit chains for the PUSCH transmission comprisessignaling that indicates one or more of the band combinations and, forthe indicated one or more band combinations, how to allocate thetransmit power budget across transmit chains for the PUSCH transmission.22. The method of claim 14, further comprising receiving signaling fromthe UE comprising at least one of: a single bit indicating whether theUE supports the skipping; a single bit per transmit precoding matrixindicator (TPMI) or TPMI group indicating whether the UE supports theskipping for the TPMI or TPMI group; or a list of TPMIs for which the UEsupports skipping at least one step of a multi-step procedure forallocating the transmit power budget across the transmit chains.
 23. Anapparatus for wireless communications by a user equipment (UE),comprising: a memory; and at least one processor coupled with thememory, the memory and at least one processor configured to: determine atransmit power budget; receive signaling indicating how to allocate thetransmit power budget across transmit chains for a physical uplinkshared channel (PUSCH) transmission, wherein the signaling indicateswhether or not the UE can skip scaling the transmit power budget by aratio of a number of antenna ports with a non-zero PUSCH transmission toa total number of configured antenna ports; allocate the transmit powerbudget across the transmit chains for the PUSCH transmission when thescaling is skipped or allocating the scaled transmit power budget acrossthe transmit chains when the scaling is not skipped; and send the PUSCHtransmission using the transmit chains according to the allocatedtransmit power budget.
 24. The apparatus of claim 23, wherein the atleast one processor and memory are further configured to providesignaling indicating whether the UE supports skipping the scaling. 25.The apparatus of claim 24, wherein the at least one processor isconfigured to allocate the transmit power budget across transmit chainsfor one or more band combinations supported by the UE for carrieraggregation.
 26. The apparatus of claim 25, wherein the at least oneprocessor is configured to provide signaling that indicates at least oneof the one or more band combinations for which the UE supports skippingthe allocating the transmit power budget across transmit chains.
 27. Theapparatus of claim 23, wherein the UE is configured to perform thescaling regardless of the signaling, depending on a rating of poweramplifiers in the transmit chains.
 28. An apparatus for wirelesscommunications by a user equipment (UE), comprising: a memory; and atleast one processor coupled with the memory, the memory and at least oneprocessor configured to: determine a transmit power budget; receivesignaling indicating how to allocate the transmit power budget acrosstransmit chains for a physical uplink shared channel (PUSCH)transmission, wherein the signaling comprises multiple bits thatindicate at least one power boosting parameter for the UE to apply afterperforming a multi-step procedure for allocating the transmit powerbudget across the transmit chains; allocate the transmit power budgetacross the transmit chains for the PUSCH transmission; and send thePUSCH transmission using the transmit chains according to the allocatedtransmit power budget and the at least one power boosting parameter. 29.The apparatus of claim 28, wherein the at least one processor and memoryare further configured to provide signaling indicating a level of powerboosting supported by the UE.
 30. The apparatus of claim 29, wherein theat least one processor and memory are further configured to compute thelevel of power boosting supported by the UE based on a reference powerlevel and a power rating of one or more power amplifiers in the transmitchains.
 31. The apparatus of claim 28, wherein the at least oneprocessor and memory are further configured to take one or more actionsto ensure applying the power boosting parameter does not result inexceeding the transmit power budget.
 32. The apparatus of claim 28,wherein: the multiple bits indicate the at least one power boostingparameter for the UE to apply on a per-port basis.
 33. The apparatus ofclaim 32, wherein the at least one processor and memory are furtherconfigured to receive signaling from the UE comprising at least one of:power boosting parameters for different ports with different bit-widths;an indication of power boosting parameters for only ports with non-zeroPUSCH as indicated by a precoder; additional signaling of power boostingparameters if the precoder changes; or an indication of power boostingparameters for all antenna ports regardless of a precoder, wherein thepower boosting parameters are applied, on a per-port basis, acrossmultiple transmissions even when the precoder changes.
 34. The apparatusof claim 24, wherein the signaling comprises at least one of: a singlebit indicating whether the UE supports the skipping; a single bit pertransmit precoding matrix indicator (TPMI) or TPMI group indicatingwhether the UE supports the skipping for the TPMI or TPMI group; or alist of transmit precoding matrix indicators (TPMIs) for which the UEsupports skipping at least one step of a multi-step procedure forallocating the transmit power budget across transmit chains.
 35. Anapparatus of wireless communications by a network entity, comprising: amemory; and at least one processor coupled with the memory, the memoryand at least one processor configured to: transmit, to a user equipment(UE), signaling indicating how to allocate a transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission, wherein the signaling indicates whether or not the UE canskip scaling the transmit power budget by a ratio of a number of antennaports with a non-zero PUSCH transmission to a total number of configuredantenna ports; and receive the PUSCH transmitted from the UE withtransmit power allocated across the transmit chains when the signalingindicates the UE can skip scaling or with a scaled transmit powerallocated across the transmit chains when the signaling indicates the UEcannot skip scaling.
 36. The apparatus of claim 35, wherein the at leastone processor and memory are further configured to receive signalingindicating whether the UE supports skipping the scaling.
 37. Anapparatus of wireless communications by a network entity, comprising: amemory; and at least one processor coupled with the memory, the memoryand at least one processor configured to: transmit, to a user equipment(UE), signaling indicating how to allocate a transmit power budgetacross transmit chains for a physical uplink shared channel (PUSCH)transmission, wherein the signaling transmitted to the UE comprisesmultiple bits that indicate at least one power boosting parameter forthe UE to apply after performing a multi-step procedure for allocatingthe transmit power budget across the transmit chains; and receive thePUSCH transmitted from the UE with transmit power allocated acrosstransmit chains based on the signaling and the at least one powerboosting parameter.
 38. The apparatus of claim 37, wherein the at leastone processor and memory are further configured to: receive signalingfrom the UE indicating a level of power boosting supported by the UE;and determine the at least one power boosting parameter based on theindicated level of power boosting supported by the UE.
 39. The apparatusof claim 37, wherein: the multiple bits indicate at least one powerboosting parameter for the UE to apply on a per-port basis.
 40. Theapparatus of claim 39, wherein the signaling indicating how to allocatethe transmit power budget across the transmit chains for the PUSCHtransmission comprises at least one of: power boosting parameters fordifferent ports with different bit-widths; an indication of powerboosting parameters for only ports with non-zero PUSCH as indicated by aprecoder; additional signaling of power boosting parameters if theprecoder changes; or an indication of power boosting parameters for allantenna ports regardless of a precoder, wherein the power boostingparameters are applied, on a per-port basis, across multipletransmissions even when the precoder changes.
 41. The apparatus of claim35, wherein the at least one processor and memory are configured toreceive signaling from the UE indicating one or more band combinationsfor which the UE supports a procedure to allocate power across transmitchains.
 42. The apparatus of claim 41, wherein the signaling indicatinghow to allocate the transmit power budget across the transmit chains forthe PUSCH transmission indicates one or more of the band combinationsand, for the indicated one or more band combinations, how to allocatethe transmit power budget across transmit chains for the PUSCHtransmission.
 43. The apparatus of claim 35, wherein the signalingindicating whether the UE supports skipping the scaling comprises atleast one of: a single bit indicating whether the UE supports theskipping; a single bit per transmit precoding matrix indicator (TPMI) orTPMI group indicating whether the UE supports the skipping for the TPMIor TPMI group; or a list of transmit precoding matrix indicators (TPMIs)for which the UE supports skipping at least one step of a multi-stepprocedure for allocating the transmit power budget across transmitchains.